1. Field of the Invention
The present invention relates to a working machine, for example, a forestry machine which is configured by utilization of a machine body of an excavator to perform drawing felled trees on the ground and gathering them, or the like, and a maintenance method for the working machine.
2. Description of the Related Art
There will be given an explanation of a background art of the present invention with reference of a swing yarder as an example of a forestry machine including a machine body of an excavator and a winch mounted thereto. The machine body of the excavator includes a lower traveling body of a crawler type and an upper slewing body slewably mounted thereon and having a cabin, and a front attachment mounted to a front portion of the upper slewing body, the lower traveler and the upper slewing body constituting a base machine. In the specification, a side of the working machine on which side the front attachment is mounted is defined as a front side of the machine, and respective directions of “front and rear” and “left and right” as to each of portions are defined based on the definition of the front side.
For example, Japanese Patent Application Laid-open No. 2008-61653 discloses a swing yarder, which includes a tower in addition to the machine body of the excavator and the winch. The front attachment includes an arm, and the tower is provided at a basal-end-side portion of the arm integrally with the arm in an upward directing attitude. The winch is mounted to the upper slewing body and driven to wind an operation rope. The operation rope is applied to a guide sheave provided at an upper portion of the tower and drawn out frontward to contribute to drawing felled trees on the ground, gathering them, or the like.
The swing yarder thus configured by utilization of the machine body of the excavator does not allow an exclusive space for installing the winch to be easily secured. The winch is therefore installed on an upper side of an existing equipment included in the upper slewing body. Specifically, the existing equipment includes a slewing motor as a slewing drive source of the upper slewing body and a control valve to control a hydraulic actuator related to the front attachment and the other hydraulic actuator; the slewing motor and the control valve are disposed on a rear side of a boom foot which is a base end portion of a boom. At a rear portion of the upper slewing body rearward therefrom, an engine room opened upward and an engine hood for opening and closing an opening portion of the engine room are provided, and the engine room accommodates an engine and related apparatus at a surrounding of the engine therein. The winch is installed over the slewing motor, the control valve, and the engine room. Particularly, if being a large-sized one, the winch is installed so as to completely close a space over the slewing motor and the control valve and also close a part of a space located over the engine hood and required for opening the engine hood.
This arrangement of the winch generates a difficulty in performing maintenance of devices to be maintained which device is disposed below the winch, namely, the slewing motor, the control valve, the engine peripheral apparatus and the like. In an ordinary excavator, respective maintenance operations of the devices are performed through respective spaces over the devices. Particularly, the maintenance for a device disposed around the engine is performed while the engine hood is opened. The winch disposed over the devices hinders the devices from their respective maintenance operations and also hinders the engine hood from being opened.
According to the arrangement, the maintenance of the devices requires the winch to be removed from the position over the devices, and this removal is not easy. In the conventional swing yarder, where the winch is fixed to the upper slewing body by a number of bolts, the maintenance requires respective operations of removing the number of bolts, lifting the entire winch by a lifting machine of a crane or the like and repositioning the winch and remounting the number of bolts following the completion of the maintenance. These operations require large-scaled equipment and involve troublesome procedures, significantly reducing an efficiency of the maintenance operation.
It is conceivable to install the winch at a high position far away upward from the devices to be maintained to thereby ensure a space for maintenance over the devices to be maintained; however, this arrangement, considerably enlarging a total height of the machine including the winch and deteriorating either of stability, mobility, and transportability of the machine, is hard to realize.